A device is known (Gasanov, A. G. et al., Patent of the Russian Federation No. 1702831 issued Jun. 27, 1997, which includes a semiconductor substrate and a matrix of semiconductor areas that have conductivity type opposite that of the substrate and that are separated from the translucent field electrode by a buffer-resistive layer with specific conductivity. Avalanche amplification of the photoelectrons takes place on the boundaries between the substrate and the semiconductor areas. The avalanche current then flows to the translucent electrode through the resistive layer situated above these areas. A shortcoming of this device is the low quantum output in the visible and ultraviolet areas of the spectrum due to the poor transparency of both the buffer layer and the highly doped semiconductor areas. In addition, there is no possibility that the photoelectrons formed between the semiconductor areas can be amplified, which leads to a reduction in the sensitivity of the device.
A device is known (Antich P. P. et al., U.S. Pat. No. 5,844,291 issued Dec. 1, 1998), which includes a semiconductor substrate with n-type conductivity and an epitaxial layer with p-type conductivity separated from the substrate by a resistive layer and a dielectric layer. Separate semiconductor areas with n-type conductivity are formed inside the dielectric layer and exit on the one side at the resistive layer and on the other—at the epitaxial layer. Highly doped areas with n-type conductivity ensure localization of the avalanche process in the p-n junctions separated one from the other by areas of the dielectric layer. The photosensitive layer where the photoelectrons are formed is actually the epitaxial layer grown on the surface of heterogeneous materials—dielectric and resistive layers. That is why the main shortcomings of the device are the complexity of the technology of preparing such epitaxial layers and the high level of dark current, which leads to deterioration of the sensitivity, and the signal-to-noise ratio of the device.
A lastly, a device is also known (Sadygov Z. Y., Patent of Russia No. 2102821 issued Jan. 20, 1998), which has been taken as a prototype and which includes a semiconductor substrate and a semiconductor layer forming a p-n junction with the substrate. The surface of the substrate contains a matrix of separate semiconductor areas with enhanced conductivity compared to that of the substrate. In the prototype, the semiconductor areas are used with the purpose of creating separate avalanche areas (micro-channels) that ensure amplification of the signal. A shortcoming of the device is the presence—and also the formation in the process of operation—of uncontrollable local micro-sparkovers in the interface regions where amplification of the photoelectrons is taking place. The problem here is that the semiconductor areas are located immediately on the p-n junction interface formed on the substrate-semiconductor layer interface. That is why the semiconductor areas have a charge and current connection between them or through the electrically neutral part of the semiconductor layer or through the substrate depending on the conductivity type. In other words, the device does not have implemented local limitation of the current in the separate areas where the avalanche process is taking place. The one or several areas with decreased sparkover potential do not permit an increase in the device voltage in order to attain a high level of the avalanche process over the whole area of the device. In this way, the device has a limited factor of amplification of the avalanche process, which is an indicator of the sensitivity level of the avalanche photodiode.